The role of ESA's Space Science Department - supporting the early and full involvement of the community of European space scientists in the definition and study of the Agency's science missions and in their design to cost - requires that the Department's staff live with these missions 'from cradle to grave'. SSD provides Study Scientists for Assessment and Phase A studies, and Project Scientists for all the following phases of the Scientific Directorate's missions. This includes commitments beyond launch (at which time Project Scientists also assume the task of Project Management), through science operations and the archive phase.
In order to keep staff in place capable of achieving these functions, it is essential that they pursue their own scientific investigations. For this purpose, the Department maintains an infrastructure and environment for research ranging from instrument development to data analysis.
In the following paragraphs we summarise, first, the context in which the Department's staff fulfilled their functional duties, then the research work and, finally, we briefly touch on contributions of SSD staff to other activities within and outside ESA.
In 1995, at the beginning of the reporting period, five Phase A studies for the third medium-size mission (M3) of the 'Horizon 2000' long-term programme were underway. Two of these were planned to explore Mars and the Moon (Intermarsnet and MORO), two concerned astronomy, namely asteroseismology (STARS) and the anisotropy of the cosmic microwave background (COBRAS/SAMBA), and one (STEP) was aimed at testing the equivalence principle, a topic in fundamental physics. The studies were completed in early 1996 and, following peer review, COBRAS/SAMBA (now Planck) was selected as the M3 project later in the year.
Four missions remained under development during 1995 and 1996. Two were the second and third Cornerstones of Horizon 2000: the XMM high-throughput X-ray spectroscopy mission and the Rosetta rendezvous mission to Comet Wirtanen. The other two were the first and second medium-size missions M1 and M2 of Horizon 2000: the Huygens Titan probe and the INTEGRAL gamma-ray observatory. In addition, technology preparation for the fourth Cornerstone, the Far Infrared and Submillimetre Telescope (FIRST), was pursued by the Study Scientist together with the Science Advisory Group throughout 1995 and 1996.
Three further missions, which had been under development at the beginning of 1995, were brought to launch readiness during the reporting period: ISO, SOHO and Cluster. The Infrared Space Observatory (ISO), which was the last project selected before the Horizon 2000 programme was defined, was launched in November 1995. A mere two weeks later, the first mission of Horizon 2000, the Solar and Heliospheric Observatory (SOHO), which belongs to the Solar-Terrestrial Science Programme (STSP) Cornerstone, was also launched.
Both spacecraft are performing flawlessly in orbit. ISO is yielding exciting new vistas of the cold and the redshifted Universe, and SOHO is providing an unequalled global insight into our daytime star and its cosmic environment.
The ill-fated Ariane flight 501 of 4 June 1996, on the other hand, resulted in a major setback. The other part of the STSP Cornerstone, four fully instrumented Cluster space-craft - marvels of magnetic cleanliness - were lost in the rocket's explosion. Recovery action with several options has been initiated and pursued by the ESA Executive, with persistent and resilient involvement of the Science Working Team, supported by the Cluster Project Scientist. The Science Programme Committee (SPC) in early July 1996 gave the go-ahead for the Phoenix mission - refurbishment of the fifth Cluster spacecraft and integration of the science instrument spares. On 3 April 1997, the SPC approved the reflight of the full Cluster mission.
The number of satellites operated in orbit rose from three (IUE, HST and Ulysses) at the beginning of 1995 to five at the end of that year, following the launches of ISO and SOHO. While the SOHO science operations followed the pattern of a Principal Investigator-type mission, where the experiment teams are fully cognizant of their instruments' observations, the ISO observatory-type mission required a large, mainly ESA-provided infrastructure for its very intense science operations. The smooth start of the mission operations and ISO's current high observing efficiency are the result of very hard work, performed sometimes under tight financial and time constraints. It should be mentioned here that a major effort, supported to a large extent by national resources, has also been devoted to the Cluster Science Data System (CSDS). This, how-ever, cannot yet be tested in the true operational environment.
At the end of 1996 the number of active scientific satellites had dropped to four. As a consequence of the reduced budget available to the Scientific Directorate following the September 1995 meeting of the ESA Council at ministerial level, it was decided to terminate the operation of the International Ultraviolet Explorer (IUE). Accordingly, the satellite was turned off at the end of September 1996, after 18 years' service to astronomers. Staff at the IUE Observatory are now completing the archive of this mission, a facility that even in its present, partially completed form has become a frequently-used tool by astronomers - some 25 000 spectra are retrieved annually.
The results of the Hipparcos mission, which ceased operating in early 1993, continued to be elaborated. This massive effort was performed by three large international consortia made up of scientists in the member states (and beyond), all coordinated by the Project Scientist. The Hipparcos and Tycho catalogues (with, respectively, 120 000 and >1 million entries) were declared final in August 1996, on schedule, yet with the astrometric and photometric results completely surpassing all original mission objectives. Data (on a total of 700 000 objects) were then shipped to the Principal Investigators, who will be able to use them during the proprietary period. During this period, which will last until June 1997, the catalogue data are being prepared for publication in printed form and as a set of CD-ROMs.
The workload on SSD's scientific, engineering and technical, secretarial and administrative staff continued to be extremely high. Staff motivation was maintained by the existence of first- rate programmes for the functional work on studies, projects and operations, as well as by a successful research programme leading to acknowledged achievements. Research Fellows, trainees and visitors contributed significantly to the scientific research in the Department.
While Science Operations are prepared in SSD's core facility at ESTEC, their execution is generally undertaken elsewhere. Science Operations staff were located over the past two years at the Space Telescope Science Institute (STScI) in Baltimore, the European Space Telescope Coordinating Facility (ST-ECF) at the European Southern Observatory (ESO) in Garching, the Ulysses operations centre at the Jet Propulsion Laboratory (JPL) in Pasadena, the IUE Observatory and the ISO Science Operations Centre at Villafranca, and the SOHO Experiment Operations Facility (EOF) at Goddard Space Flight Center.
The range of disciplines covered by SSD's activities has remained unaltered over the past two years. However, work on fundamental physics has increased and, in astronomy, more emphasis is now being put on the infrared and submillimetre range, in anticipation of the Planck and FIRST missions.
In research, where major progress was made in the development of superconducting tunnel junctions, the adaptation of atomic- force microscopy selected for flight on Rosetta is now also pursued. Initial steps toward design studies for a drag-free attitude control system (as part of a new satellite concept called 'sciencecraft') were also taken. With the launches of SOHO and, in April 1996, the Italian-Dutch SAX X-ray satellite, additional SSD experiments [one built in SSD in its entirety (SAX) and others developed in collaboration with other institutes (SOHO)] are now operated in orbit and have already yielded the first results. In addition, investigations are carried out with data obtained by previously launched SSD-related instruments (in particular on Ulysses, Wind, Polar and the Compton Gamma Ray Observatory), as well as with investigations using observing time on other space-borne facilities and ground-based telescopes.
The Department's annual ESLAB Symposia continued, with the topics Towards the Source of Gamma-Ray Bursts in 1995 and Submillimetre and Far-Infrared Space Instrumentation in 1996. In addition, several Workshops (on Astrometry, in preparation for Huygens, INTEGRAL and FIRST, and on data of HST, ISO and SOHO) were held. Within ESA, SSD organised fortnightly seminars, mostly with outside speakers, as well as occasional colloquia on subjects of interest to an ESTEC-wide audience.
SSD staff were frequently called upon to give advice on Agency matters outside of the Scientific Directorate. For example, on the Technical Research Programme (TRP), in the ESA Space Debris Advisory Group and for ESA's International Affairs Office. Staff also participated in scientific conferences, often as invited speakers or as organisers of special sessions; some teach courses on space science at Universities in the member countries.
This report, it is hoped, will convey the breadth of functional and research work being performed by the staff of SSD. It provides details on the manpower deployment and includes a listing of the publications that have appeared during the past two years.
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Head of Department: M.C.E. Huber Deputy: A. Pedersen Admin. Assist.: C. Bingham
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Divisions Solar System Division Astrophysics Division
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Division Head K.-P. Wenzel B.G. Taylor
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Scientists T. Appourchaux J.P.Lebreton M. Bavdaz A. Parmar
A. Chicarro R.G. MarsdenK. Bennett A. Peacock
V. Domingo R. Reinhard F. Favata M. Perryman
B.H. Foing T.R. Sanderson M. Fridlund G. Pilbratt
R. Grard R. Schmidt P. Jakobsen A. Salama
Y. Jafry G. Schwehm M. Kessler J. Tauber
D. Martin G. Thörner
L. Metcalf C. Winkler
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Projects Ulysses EXOSAT
SOHO IUE
Cluster (STSP, Cornestone) Hipparcos
Phoenix HST
Huygens/Cassini ISO
Rosetta (Cornerstone) XMM (Cornestone)
FIRST (Cornestone)
INTEGRAL
Planck
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Studies MiniSTEP STARS
Mission to Mercury Lunar Studies
LISA GAIA
Intermarsnet Darwin
MORO and other Lunar Studies
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Research Areas Solar Physics Astronomy (gamma rays to radio)
Space Plasma Physics Detector Research and Development
Planetary Physics Archive Development and Maintenance
Fundamental Physics
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Research M. Desai D. Hestroffer
Fellows L. Fletcher E. Kuulkers
B. Jacobsen T. Oosterbroek
K. Muglach A. Orr
J. Romstedt F. Pelaez
R. van Dijk
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IUE Observatory
Head: W. Wamsteker
M. Barylak R. Gonzalez P. Rodriguez N. Schartel
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XMM Scientific Operations Centre
M. Dahlem C. Erd Ph. Gondoin F. Jansen
D. Lumb R. Much J. Riedinger G. Vacanti
I. Zayer
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ISO Science Operations Centre (Villafranca)
B. Altieri J. Clavel K. Leeck R. Siebenmorgen
C. Arviset R. Fontaine J. Munoz Peiro D. Texier
J. Audric J.C. Gabriel L. Orsini N. Trams
P. Barr A. Hears S. Ott
M. Burgdorf A. Heske T. Prusti
P. Claes R. Laureijs B. Schulz
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ISO Science Operations Support (ESTEC)
G. Dreschsel L. Osterman
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Space Telescope European Coordinating Facility
Head: P. Benvenuti
R. Albrecht A. Caulet R. Fosbury A. Micol
M.R. Rosa
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Space Telescope Science Institute
Head: F. Macchetto
D. Axon S. Casertano H. Jenker C. Skinner
P. Bely A. Clampin-Nota M. Miebach M. Stivelli
C. Burrows L. Colina P. Moeller
C. Cacciari P. Goudfrooij N. Panagia
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INTEGRAL Science Operations Centre
C. Breneol I. Chambers L. Hansson J. Sternberg
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STSP Science Operations
C.P. Escoubet B. Fleck P.C. Martens L. Sanchez
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Rosetta Science Operations
R. Schulz
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Ulysses Science Coordination
D.E. Page
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